“The edict came down during Roy Oswalt’s first season in Double A. Thou shalt throw changeups, the Astros brass said, and thou shalt throw them at least 20 percent of the time.

Needless to say, young Oswalt was not pleased. He was in the middle of a spectacular season – he’d finish at 15-7 with a 2.21 ERA – and was hellbent on reaching the majors via the shortest possible route. That route did not include shelving a dominant fastball and curveball in favor of a pitch he’d never thrown with any sort of success. But the brass had spoken, and that was that.

Undeterred, Oswalt took matters into his own hands. He opened up his next start with a changeup, which he followed with another changeup, and then another. Then 10 pitches into the outing, a puzzled Mike Maddux – then the pitching coach for the Round Rock (Texas) Express – trotted out to the mound.

“Your arm hurt?” Maddux asked.

Oswalt shook his head.

“Nah,” he said. “I’m trying to get those changeups out of the way so I can pitch.”

As Oswalt relayed the story earlier this week, he cackled like a kid who once fed his broccoli to the family dog. Because he knows full well that this season, his old nemesis has become one of his best friends.

Ten years into his career, Oswalt has finally found a changeup grip that works for him. And his sudden utilization of the pitch is one of the big reasons why he enters tonight’s start against the Nationals with some of the best numbers of his already-prolific career.

“I bet you I’ve thrown my changeup more this season than I have in 10 years in the majors,” Oswalt said earlier this week with a wry grin.

For most of his storied career, the veteran righthander has been as meat-and-potatoes as a Mississippi Ponderosa, attacking hitters with his fastball and fooling them with his curve and slider. He had the ability to throw his changeup for a strike. Most times, he could do it without pinching his nose. But it wasn’t a weapon.

“His changeup back then was, I don’t want to say a work in progress, but it was more of a change of pace pitch to show hitters that he had one,” said Phillies closer Brad Lidge, who played with Oswalt in Houston from 2002-07. “But his curveball was so deadly back then he almost didn’t need to throw the changeup that much.”

This offseason, Oswalt began experimenting with a new grip on his changeup, switching from a classic circle-change to what is known as a “Vulcan” or “Fosh.” The grip looks a lot like how Dr. Spock might throw a changeup, the ball jammed between the middle and index fingers in a sort of live-long-and-prosper configuration.

Oswalt took the pitch for a test run this winter at Mississippi Junior College, where he threw live batting practice to his alma mater’s team. He continued to work on it during spring training, and by the time the regular season started, he felt like he had added a new pitch to his arsenal.”